Depends on what you mean with 'automatically' and 'updated with new data' (only new records, or also deleted and changed?). And what you want to do with the QVD.
Maybe have a look at
I don't realise it will be different treatment for different situation of changes.
I want to set up individual QVD for each dimension, e.g. Month, Year, Company, Country, Products etc, so those dimensions will only be new and updated records.
(Please let me know if my approach is bad)
Then I want to set up more QVDs for facts/measures, e.g. list of all investments (by Month, Year, Company, Investments ID, etc), list of sales (by Month, Year, Company, Sales ID, Products), so those records can be new, updated and deleted.
At the moment, the export text files don't have any date stamp in the file (it can be added if needed).
Then, I want to create an apps to load data from those QVDs.
I am hoping I can build the QVDs to update all the new, updated, or deleted data automatically (or at certain time), so that the apps can use the latest data.